<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
<script>
    var MathCopy = {};
    Object.defineProperty(MathCopy,"PI",{
        value:3.141592654,
        writable:false,
        configurable:false,
        enumerable:true
    })
    MathCopy.PI=1;
    console.log(MathCopy.PI)
</script>
</html>